1. Field of the Invention
The present invention relates to an expansion ring assembly for sealingly installing a gasket within the opening of a structure to provide a sealed connection between the structure and a pipe extending through the structure opening.
2. Description of the Related Art
In underground pipe systems, it is often necessary to connect a pipe in a sealed manner within an opening in the wall of a structure, such as a manhole riser or monolithic base, or a septic tank or fluid distribution box, for example. Typically, a flexible elastomeric gasket is placed within the opening in the wall, followed by fitting an expansion ring against the interior surface of the gasket. A suitable expansion mechanism is used to radially expand the expansion ring and to lock the ring in an expanded condition in which the gasket is sealingly compressed between the expansion ring and the opening in the wall of the structure. Thereafter, a pipe is inserted through the gasket, and one or more external take-down clamps are installed around a boot portion of the gasket which extends from the wall to sealingly compress the gasket boot between the clamps and the outer surface of the pipe. In this manner, a sealed connection is made between the pipe and the structure.
One known expansion ring includes a ratcheting engagement between overlapping ends of the ring. When the ends of the ring are forced in opposite directions from one another as the ring is radially expanded, ratchet teeth on the ring ends sequentially engage one another, wherein the expansion ring may be sequentially expanded in an incremental manner into multiple locked positions. A separate tool, such as a hydraulic or pneumatic jack, is used to engage the opposite ends of the expansion ring and to drive same apart from one another. Typically, such tools can be cumbersome to use in the field and tend to be expensive, as the tools are custom designed for use only with particular types of expansion rings.
Other known expansion mechanisms for expansion rings include cooperating, linearly movable, wedge-type cams which are actuated by rotating a threaded bolt which extends through portions of the cams. These devices tend to include a large number of parts, are spatially cumbersome and bulky and, due to the need to rotatably drive the threaded bolt, cannot be installed quickly.
What is needed is an expansion ring assembly which is an improvement over the foregoing.